networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

    @@
    expression SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - fn(SKB, LEN)[0]
    + *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 5 insertions, 5 deletions

diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 3a0c94590411..7b2bdda1514c 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -727,7 +727,7 @@ static int hci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
 				break;
 		}
 
-		*skb_push(skb, 1) = 0;	/* CTR, see spec:10.2.2.1 */
+		*(u8 *)skb_push(skb, 1) = 0;	/* CTR, see spec:10.2.2.1 */
 
 		hdev->async_cb_type = HCI_CB_TYPE_TRANSCEIVE;
 		hdev->async_cb = cb;
diff --git a/net/nfc/hci/llc_shdlc.c b/net/nfc/hci/llc_shdlc.c
index 9ab4a05f086f..5bd4529279f5 100644
--- a/net/nfc/hci/llc_shdlc.c
+++ b/net/nfc/hci/llc_shdlc.c
@@ -160,7 +160,7 @@ static int llc_shdlc_send_s_frame(struct llc_shdlc *shdlc,
 	if (skb == NULL)
 		return -ENOMEM;
 
-	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
+	*(u8 *)skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
 
 	r = shdlc->xmit_to_drv(shdlc->hdev, skb);
 
@@ -178,7 +178,7 @@ static int llc_shdlc_send_u_frame(struct llc_shdlc *shdlc,
 
 	pr_debug("uframe_modifier=%d\n", uframe_modifier);
 
-	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
+	*(u8 *)skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
 
 	r = shdlc->xmit_to_drv(shdlc->hdev, skb);
 
@@ -551,8 +551,8 @@ static void llc_shdlc_handle_send_queue(struct llc_shdlc *shdlc)
 
 		skb = skb_dequeue(&shdlc->send_q);
 
-		*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) |
-				    shdlc->nr;
+		*(u8 *)skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) |
+					shdlc->nr;
 
 		pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns,
 			 shdlc->nr);